Method of trowelling a coating material onto a building block



E. C. HALL Dec. 17, 1968 METHOD OF TROWELLING A COATING MATERIAL ONTO A BUILDING BLOCK Filed Feb. 25, 1965 YINVENTOR. By 111! 61 Hall, @Jaw ATTORNEYS.

United States Patent 3,416,947 METHOD OF TROWELLING A COATING MA- TERIAL ONTO A BUILDING BLOCK Earl C. Hall, Broomall, Pa., assignor to M. A. Bruder &

Sons Incorporated, Philadelphia, Pa., a corporation of Pennsylvania Filed Feb. 25, 1965, Ser. No. 435,308 2 Claims. (Cl. 117-64) ABSTRACT OF THE DISCLOSURE The method used is to measure continuously the surface contour of building blocks and relative heights of succesive blocks prior to the arrival of such blocks at the trowel, and transmitting such measurements to adjust the height of the trowel over each block so measured as it arrives under the trowel, thereby to compensate for irregularities in the surface of individual blocks so as to provide a smooth coating of uniform thickness upon each block.

This invention relates to a method and apparatus for finishing building materials and, more specifically, to the art of coating masonary building blocks or tiles.

The general concept of treating masonry building units, such as cement or cinder blocks, with a coating material in paste form for purposes of waterproofing, tinting and smoothing is known.

In the past, means for depositing and spreading filler paste have usually comprised a unit having a conveyer belt for carrying the blocks under a paste applicator plus one or more trowels to spread the material over the surface of the blocks. See, for example, US. Patents 2,504,205 and 2,946,110.

One significant drawback of prior devices, however, is their failure to produce a coating of uniform thickness upon successive blocks having significant differences in height, or upon a single block having surface faults in the form of valleys and ridges extending transversely of the block. This drawback may be traced to the fact that, in the main, past devices utilized trowels which are maintained at a fixed height above the conveyer belt carrying the blocks. The provision of a trowel adapted to move transversely of the incoming blocks (US. Patent 2,504,205) or a floating trowel adapted to be pushed upwardly by accumulated deposits of coating material only when these deposits arrive directly under the trowel (US. Patent 2,946,110) do not yield'a uniform coating on blocks having the aforementioned characteristics. In the case of the device disclosed in the last mentioned patent, for example, the trowel may be caused to float vertically, but not in response to blocks of uneven height, but merely in response to greater or lesser accumulations of coating material on a given block.

The general object of this invention is to provide a method, and apparatus to perform the method, for trowelling the coated surfaces of building blocks and the like so as to produce a uniform coat upon each block.

The method used, broadly speaking, is to measure continuously the surface contour of each block and relative heights of successive blocks prior to the arrival of such blocks at the trowel, and transmitting such measurements to adjust the height of the trowel over each block so measured as it arrives under the trowel, thereby to compensate for irregularities in the surface of individual blocks and for difi'erences in height between successive blocks so as to provide a smooth coating of uniform thickness upon each block. I

The apparatus of the present invention, generally defined in a non-limiting manner, includes preferably a "ice blade; a plurality of runners positioned in front of the the surface of the incoming blocks prior to their arrival trowel or doctor blade mounted for movement toward blade; means for maintaining the runners in contact with or away from the surface of blocks passing beneath such under the blade, while also permitting the runners to move vertically to follow uneven contours in individual blocks and in response to differences in height between successive blocks; and means for transmitting the vertical movement of the runners to adjust the height of the trowel blade over the blocks to compensate for such uneven contours and height differentials.

Further advantages and particulars of this invention will be evident from the following description and from the drawing wherein:

FIG. 1 is a perspective view of a preferred embodiment of the appartus of this invention;

FIG. 2 is an enlarged sectional view taken on the line II-II of FIG. 1; and

FIG. 3 is a sectional view of one of the runners taken along the lines III-III of FIG. 2;

FIG. 4 is a schematic view in side elevation of adjacent cinder blocks.

In describing the method and the preferred embodiment of the apparatus of this invention illustrated in the drawing, specific terminology has been resorted to for the sake of clarity. However, it is not the intention to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

In FIG. 1 there is shown a series of cinder blocks, including that indicated by the numeral 1, carried by a conveyer belt 2 which passes over, and is supported by, a table 3 having a base 4 and guide rails 5 and 6. As indicated by the arrows, the blocks are moving from right to left in FIG. 1.

Supported by guide rails 5 and 6 are upright side plates 7 and 8 which serve to restrain lateral displacement of the blocks during the hereinafter described trowelling operation.

Also shown in FIG. 1 are pipes 9, 10' for supplying coating material, equipped with fan-like discharge nozzles 11, 12 adapted to deposit a first coat 13 and a second coat 14 of material in paste or cream form across the surface of the incoming blocks. As is typical, the deposited material forms a lumpy, uneven coat, as at and 16.

Anterior to discharge nozzle 11 is a trowel or doctor blade assembly 17' for leveling and smoothing the coating material deposited by said nozzle. A second doctor blade assembly 17 is positioned behind nozzle 12 for performing the same function on the coating deposited by nozzle 12. It is sufficient to describe particularly only the elements comprising assembly 17 since this assembly is identical to assembly 17'.

The assembly 17 includes a doctor blade 18, each end portion of which is contained against longitudinal movement by insertion into slots -19 and 20 formed in the top portions of side plates 7 and 8. By means to be described, the blade 18 may move vertically within the slots 19 and 20.

Affixed at right angles to blade 18 is a pair of braces 21, 22 which extend rearwardly from the blade in the direction of the nozzle 12. Inserted within a bore 30 drilled through brace 22 is a rounded stud or leg 23, at the bottom of which is afiixed a runner 24. The upper portion of leg 23 is inserted in a slot 25 formed in horizontal top portion 26 of a standard 27. Top portion 26 is maintained parallel to blade 18 at a position to the rear of, and at greater height than, said blade by depending arms 28, 29, of the standard, affixed to side plates 7 and 8 respectively.

The slot 25 in standard portion 26 is of slightly larger width than leg 23 and leg 23 may therefore reciprocate vertically therein as runner 24 encounters lateral valleys, such as 38, or ridges, such as 39 in the surface of incoming blocks, or in response to successive blocks of different heights such as is indicated at 40 in FIG. 4. It is to be noted that runner 24 has a knife-like lower edge 31 which cuts through the coating paste to the surface of the blocks. Thus, vertical movement of the runner occurs only in response to variations in the actual surface of a given block or differences in actual surface heights between successive blocks, and not in response to uneven accumulations of the coating paste. It is also to be noted that runner 24 has a rounded leading edge 32 which enables the runner to climb steep lateral ridges or edges.

As shown in FIG. 2, leg 23 is threaded to receive a nut 33 under brace 22 and a nut 34 over top portion 26 of standard 27. Thus, as runner 24 rises as it encounters a raised ridge, etc., leg 23 also rises, and since nut 33 has a larger diameter than bore 30, brace 22 also moves upward. In turn, blade 18 which is attached to brace 22 also rises as the ridge, etc., passes below.

A coil spring 35 embracing leg 23, the ends of which rest against washers 36 and 37 adjacent the bottom of standard portion 26 and the top of brace 22 respectively, serves to urge the brace 22 downwardly against nut 33. The spring exerts enough downward force to maintain the runner 24 against the surface of the incoming blocks at all times, but also permits the leg 23 to rise when the runner 24 encounters a ridge, etc. The spring also functions to press the runner 24 into lateral depression or valleys in the face of the incoming blocks, like that indicated at 38 in FIG. 4. The extent of downward movement of runner 24 can be adjusted by means of turning nut 34.

As shown in FIG. 1, the braces 21, 21' and 22 are equipped with runner assemblies identical to that just described in conjunction with brace 22 and runner 24, the corresponding elements of which are indicated by the suffixes a, b and c respectively. Thus, the blade 18 is equipped with a pair of runners 24, 24a and blade 18 with a pair of runners 24b, 24 each pair of said runners being equipped to raise or lower their respective blade in response to surface variations of a given block or between successive blocks.

It'is preferable to provide means whereby the distance between side plates 7 and 8 may be automatically adjusted to compensate for variations in width between successive incoming blocks. For this purpose, braces 41, 41' for plate 7, similar braces (not shown) for plate 8, and top portions 26, 26 of standards 27, 27 may be constructed as shown in FIG. 1.

Brace 41, for example, comprises an angle iron 42 atfixed to rail 5, the horizontal leg of which is formed with an upright tab 43 having a bore 44 for the reception of a reciprocating stud 45, one end of which is attached to plate 46 secured to side plate 7. A coil spring 47 surrounds that portion of stud 45 between tab 43 and plate 46 and, by exerting oppositely directed force upon tab 43 and plate 46, serves to urge side plate 7 inwardly while at the same time permitting the plate 7 to move outwardly in response to a wider than normal block. Stud 45 is formed with an enlarged head 48 which prevents the stud from being withdrawn from bore 44 of tab 43 when there are no blocks between side plates 7 and 8. Brace 41' has the same construction, as do the braces for side plate 8.

As plates 7 and 8 are moved relatively toward or away from each other in response to blocks of varying width it isnecessary that the top portions 26, 26' of standards 27, 27' be adjustable to compensate for such change. Thus, each top portion may be comprised of two telescopically engageable sections, as indicated by the dotted lines in FIG. 1. In this connection, it will be understood that runner legs 23-23c will occupy different positions in their respective slots 25-250 as the portions 26, 26' change in length.

It will be understood that the runners for a given blade may move vertically by the same amount at the same time, thus maintaining the blade level as it is raised or lowered. In addition, it is to be noted that each runner for a given blade may move vertically independently of any vertical movement of the other runner supporting the blade. Thus, when a block which has a top surface which slopes from one lateral edge to the other lateral edge arrives under the runners, each runner will move vertically by a different amount according to the amount of the slope or incline. In turn, the blade will tilt (with respect to the horizontal plane of the conveyor 'belt 2) and will therefore produce a trowelled coat which will have the same slope as the surface of the block and which will be of uniform thickness over such surface. In practice, the degree of blade tilt is relatively slight since the difference in height between the lateral edges of a building block, such as a cinder block, is normally only .12 to .30 inch.

At this point, it will be observed that the presently illustrated apparatus is designed to automatically perform a method which could be performed by hand measurement and adjustment of the scraper blades 18 and 18'. However, the hand operation would be so time consuming as to be impractical.

With reference to the specific apparatus shown, the method can be characterized as: (l) measuring the surface of incoming blocks prior to their arrival at the scraping blade, and (2) transmitting such measurements to adjust the height of the blade to compensate for such variations so that a uniform layer of coating material will be produced, i.e., so that the thickness of the coat on a flat surface portion of a given block is the same as the thickness of the coat over a depressed or raised surface portion of the block. In terms of the present apparatus, the vertically movable runners provide the measurement and, in conjunction with nut 33 (for raised portions) and spring 35 (for depressions) transmit this measurement to blade 18 via brace 22 with a sutficient amount of power to raise or lower the blade by an amount equal to the measured variation.

It will be understood that the foregoing characterization of the method of this invention is for explanatory purposes and is not intended to be limiting.

Various modifications of this invention, all of which are intended to be covered in the claims, are apparent. For example, the distance between the runners and the adjacent edge of the blade may be varied from zero to several inches or more. The exact spacing necessary to ensure that the blade moves vertically just as a ridge, etc. passes therebeneath will depend primarily upon the rate at which the conveyer belt carries the blocks.

It is to be clearly understood that the terms and expressions used herein are employed as terms of description, and not of limitation, and that there is no intention in usingsuch terms and expressions to exclude any equivalents of the apparatus or method described. It is also to be clearly understood that what is specifically shown and described herein represents a preferred embodiment only of the invention, and that various changes and equivalents may be resorted to without departing from the principles of the invention or the scope of the claims hereof. Accordingly, it is intended to claim the present invention broadly, as well as specifically, as indicated in the appended claims.

Having thus described my invention, I claim:

1. A method of troweling a coating material onto a moving contoured surface of a building block with a doctor blade comprising the steps of:

(a) moving a contoured surface of a building block having coating material disposed thereon in a path directed to pass said surface below doctor blade means,

(b) monitoring each successive portion of said surface prior to the arrival thereof under said blade means,

(c) transmitting an impulse in response to any variation in surface contour, and

(d) adjusting the position of the blade means With respect to said surface in response to said impulse as the variation in surface contour passes beneath said blade means.

2. A method of troweling coating material onto a contoured surface of a building block comprising the steps of:

(a) moving a surface of a building block having coating material disposed thereon toward a troweling zone,

(b) monitoring each successive portion of said surface prior to the arrival thereof at the troweling zone to produce measurements of the contour of said surface,

(0) transmitting said measurements to said troweling zone,

References Cited UNITED STATES PATENTS 2,504,205 4/ 195 0' King. 2,588,595 3/1952 Warner. 2,946,110 7/1960 Lang.

DONALD J. ARNOLD, Primary Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,416,947 December l7, 19

Earl C. Hall It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, li 1,, b gi ni with "blade; a plurality" cancel all to and including "beneath such" in line 5, same column 2, and insert trowel or doctor blade mounted for movement toward or away from the surface of blocks passing beneatl such blade; a plurality of runners positioned in front of the blade; means for maintaining the runners in contact with the surface of the incoming blocks prior to their arrival Signed and sealed this 10th day of March 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

